Centrifugal blasting machine



Dec. 29, 1959 K. H. BARNES 2,918,758

CENTRIFUGAL BLASTING MACHINE 4 Sheets-Sheet 1 Filed Jan. 30, 1957 Fr 2 KINVENTOR.

K 71226272 Jf. Barnes Dec. 29, 1959 K. BARNES 2,913,758

CENTRIFUGAL BLASTING MACHINE Filed Jan. 30, 1957 4 Sheets-Sheet 2 FlaF2624 INVENTOR.

Ker/126171 H Ear-Hes J 7' fl zerzz Dec. 29, 1959 K. H. vBARNES 2,918,758

CENTRIFUGAL BLASTING MACHINE Filed Jan. 30, 1957 4 Sheets-Sheet 3INVENTOR. Kennefh Ji. Barnes BY gnu, M

- flh orrz 61 5 Dec. 29, 1959 K. H. BARNES Filed Jan. 30, 1957 4Sheets-Sheet 4 United States Patent CENTRIFUGAL BLASTING MACHINE KennethH. Barnes, South Bend, Ind., assignor to Wheelabrator Corporation,Mishawaka, Ind., a corporation of Nebraska Application January 30, 1957,Serial No. 637,109

11 Claims. (CI. 51-13) This invention relates to a machine in whichabrasive particles are thrown at high velocity upon work continuouslybeing tumbled within a confined space to clean the surfaces of the work,as in the removal of sand from metal castings or burrs and flashing frommolded parts, and it relates more particularly to a blasting machine ofthe type described embodying improvements which enable more eflicientuse and operation of the machine and decreased costs in operation fromthe standpoint of wear and replacement of parts, and it is an object ofthis invention to produce a machine embodying such improvements.

More specifically, it is an object of this invention to produce ablasting machine of the type described which provides greater access tothe interior thereof for the introduction and removal of work; whichembodies means of protecting parts otherwise exposed, to minimize workdamage and destruction of parts thereby, not only to increase the lifeof the elements of the machine but materially to increase the capacityand output of the machine; which enables automatic operation for openingand closing the machine in loading and unloading the machine; whichembodies means to prevent loss of abrasive material from the machine tothe surrounding atmosphere during operation; which prevents abrasive andwork from becoming lodged between parts of the machine in operation tojam the machine or otherwise cause damage or breakdown of parts, andwhich combines these improvements in combination with an improvedendless carrier upon which the work rests to improve the operation ofthe machine and its efliciency in operation.

These and other objects and advantages of this invention willhereinafter appear and, for purposes of illustration, but not oflimitation, an embodiment of the invention is shown in the accompanyingdrawings, in which Figure 1 is a perspective front elevational view of amachine embodying features of this invention;

Figure 2 is a sectional view taken along the line 22 of Figure 1,showing the door guide structure in detail;

Figure 3 is a fragmentary elevational view in perspective of the frontside portion of the machine showing the shielding for protecting theelements of the machine in the wider door opening;

Figure 4 is a fragmentary view in elevation from the inside of the doorstructure shown in Figures 1 and 2;

Figure 5 is a sectional view taken along the line 5--5 of Figure 4;

Figure 6 is a front elevational view of the side frame structure of themachine;

Figure 7 is an elevational view of the inside of the side structure ofthe machine shown in Figure 6, with elements of the machine omitted toenable illustration of the details of the machine; and

Figure 8 is a sectional elevational view of the bottom portion of thedoor structure of the machine.

Description will be made hereinafter to the various improvementsembodied in a blasting machine of the type described in the Peik PatentNo. 2,104,055 and the Turnbull Patent No. 2,131,772. On occasion,reference will be made to the structure of the prior art as representedby the aforementioned patents to point out deficiencies which areovercome by the practice of this invention.

Referring now to Figures 1 and 3, the numeral 10 represents flight barswhich are arranged with the front and back edges in overlapping relationone with the others adjacent thereto to provide a continuous surface onwhich the work to be blasted is carried for tumbling. The ends of theflight bars are secured to pads (not shown) which extend inwardly fromlink members pivoted one onto the other in endless succession to providea continuous link chain which operates about rollers, as represented bythe roller 12 at the front or door portion of the machine and whichincludes a similar roller member for rotational movement about aparallel axis rearwardly and below the first roller and which alsoincludes a driving sprocket mounted for rotational movement about aparallel axis above the first roller and rearwardly thereof.

The top flight of the endless belt,.as guided by th link chains, turnsabout the periphery of spaced drums 14 located between the roller 12 andthe sprocket to define a line of travel which proceeds from the roller12 downwardly as deflected about the lower periphery of the drum 14 andup the rear edge to the sprocket which is located forwardly and abovethe inner periphery of the drum so that the belt traveling with the linkchain forms a valley wherein most of the work rests, and a portion whichextends upwardly and forwardly from the rear of the valley to cause thework to rise and tumble forwardly as the chain link and flight bars areadvanced in operation in the direction of the arrow in Fig. 3. Whenunloading the machine, the direction of movement of the chain link andattached flight bars is reversed so that the work will be carriedforwardly over the hump provided as the chain link turns about theroller 12 to pass rearwardly beneath the upper flight and up toward thesprocket. The flight bars, the chain links, and the attached parts, formno portion of the invention and therefore a detailed description thereofwill not be given except by way of reference to the aforementionedcopending application.

Suffice it to say that the drums 14, separately mounted for rotationalmovement and lined on their inner surfaces with wear plates 16, form theside walls of a space having for its bottom and back walls the endlessbelt of flight bars traveling about the periphery portions of the drums.The space is concealed at its top by the sheet metal housing 18 and atits front by a door 20 mounted for shifting movement between openposition for loading and unloading the space with work and a closedposition for concealing the space with the work carried on the beltconveyor for treatment. When the work space is concealed, abrasiveparticles can be thrown downwardly centrifu'gally at high velocity byone or more centrifugal blasting wheels 22 mounted on the top of thehousing with the spray pattern of abrasive particles directed downwardlyonto the work throughe suitable openings in the top wall of the housing.

An important concept of this invention resides in the means forenlargement of the access opening to the machine for loading andunloading the work. To the present, the access opening has been confinedto the space between the drums 14 since, otherwise, difficulties havebeen encountered in the protection of the chain links and rollers onwhich the flight bars are carried. Exposure of such elements and thewalls of the housing to the abrasive particles bounding and reboundingwithin the-confined space would quickly lead to theiracompletedestruction. It was believed necessary also to confine the opening tothe area between the drums in order to effect a suitable seatingrelation which minimizes the entrance of abrasive particles into spacesbetween moving elements and to avoid the entrance of work or portionsthereof into openings between the drum, roller, flight bars or chainlink members whereby continued operation of the machine might causedistortion or destruction of parts, thereby to cause shutdown of theunits for repair or for replacements of parts.

Even though limited to the space between the drums 14, many of thedifllculties previously pointed out were still being experienced byreason of the spaced relationships existing between the flight bars inoperation and between the ends of the flight bars and the drums and doormembers whereby abrasive particles were lost or thrown into theatmosphere and work or portions thereof Were able to become lodgedbetween the moving parts to cause jamming.

Enlargement of the access opening is achieved in accordance with thepractice of this invention with concurrent improvement in the protectionof parts by the modification in the construction to include a shieldingmember 22, illustrated in Figs. 3, 6 and 7 of the drawings, as a metalcasting which fits tightly over the roller 12 over which the link chaintravels at the front end of the machine. The shielding member 22, formedof an abrasive and wear-resistant metal, comprises a rearward andupwardly extending portion 24 of curvilinear shape corresponding to theperiphery of the drum and dimensioned to cover the space between theperiphery of the drum adjacent the roller and the side wall 26 of thehousing to conceal the space therebetween.

Extending forwardly integrally from the roller edge portion of theupright curvilinear section 24 is a forwardly extending portion 28concentric with the roller 12 and dimensioned to extend crosswisebetween the adjacent edge portions of the flight bars 10 and the sidewall 26 of the housing to conceal the space therebetween. The twocurvilinear portions converge one into the other and extend beyond thepoint of convergence to form a nose piece 30 which projects rearwardlyand downwardly into the region between the roller 12 and the drum 14 toeffect a separation therebetween which provides further protectionagainst the formation of open spaces between the drum and roller throughwhich abrasive particles might be thrown against the chain links or thehousing walls to cause wear or deterioration.

The shield 22 comprises an integral member having a side wall section 32provided with openings for attachment of the shield, as by bolts 34, tothe side wall of the housing or to the frame of the machine. Thecurvilinear portion 28 concentric with the roller 12 and which extendsabout the chain links is provided with a downturned apron or flange 36at its inner euge and which extends downwardly to a level below the topsurfaces of the flight bars 10 as they pass with the chain about theroller 12 to provide a sealing relation between the shield and theflight bars sufiicient to prevent openings of a dimension in which workmight become entrapped.

The shielding member 22 extends forwardly for a distance beyond theeffective range of the abrasive particles being thrown in the work spaceand to a position to be contacted by the door 241, seen in closedposition, thereby etfectively to seal the work space from the otherparts of the machine and the outside atmosphere. Thus the access openingat the front of the machine has been extended beyond the spaced drums toinclude the space covered by the chain links and rollers, thereby tomake available the entire area between the side walls of the housing.The increase in the access opening makes the work space more readilyavailable for loading and unloading with less danger of the wear ordestruction of parts.

In addition to the increase in the dimension of the opening for loadingand unloading the machine, the described improvement makes it possibleto embody a door structure which offers a better sealing relation forpreventing loss of abrasive materials in operation and better protectionof the door structure while also making it possible to employ a doorassembly which is amenable to automatic operation for opening andclosing movements In the past, with the smaller door opening, use hasbeen made of a flat metal plate pivotally mounted for rocking movementabout its upper edge portion to between open and closed positions. Theplate was dimensioned to cover the open space between the top wall ofthe housing and the portion of the flight bars traveling over theforward periphery of the roller in the attempt to conceal the Work spacetherebetween. The plate was provided with a resilient apron extendingfrom the lower edge thereof which was adapted to be draped by hand aboutthe curvilinear portion of the roller and flight bars in the attempt toprovide greater protection to the operator and to the machine parts. Thedoor assembly described was incapable of providing a sufficiently tightseal for the protection desired, and it required consider able manualoperation and adjustment in use.

in construction of a door for automatic operation and for better sealingand protection, it has been found desirable to subdivide the doorstructure into separate components, one of which comprises a straightsection capable of linear movement to enclose the straight run betweenthe hump of the flight bars traveling about the roller and the upper endof the access opening, and the other of which comprises a flexiblemember capable of shifting movement in a curvilinear path to cover thatportion of the opening about the roller beneath the lower edge of thedrum and which extends continuously from the lower edge thereof to thelower end of the access opening.

Referring now to Figs. 1, 2, 5 and 6 of the drawings, the upper doorpart it is formed of a heavy metal plate 42 dimensioned to have a widthcorresponding to the width of the opening between the side walls 26 ofthe machine housing and a length corresponding to the distance betweenthe upper end of the door opening ad jaccnt the top wall of the housingand the tangent with the periphery of a cylinder slightly greater thanthe cylindrical section formed by the flight bars traveling about theroller 12. The door plate is preferably provided with reinforcing andstiffening members on its outer face, preferably adjacent its edges, asrepresented by the panel members or beams 44, fixed to the outer wallsof the plate, as by welding or the like.

The inner wall of thet door plate is protected from wear by the abrasiveparticles by a replaceable rubber blanket 46 which is held by aplurality of hold-down straps 4:; of wearresistant material. The strapsare fixed to the door plate to grip the rubber lining 46 therebetween bymeans of bolts 50 or other equivalent securing means. The rubber lining46 and the hold-down plates 48 terminate short of the lateral edges ofthe door plate 42 by an amount to permit the attachment of wear plates52 in the form of a plurality of elongate sections of wear-resistantmaterial to be secured to the lateral edges along the side wall of thedoor plate, as by bolts 54. The wear plates are secured in end-to-endrelation to provide a continuous surface capable of functioning as abearing surface in sliding relation with a door frame member 56 duringmovement of the door plate between raised and lowered positions ofadjustment.

A guide flange 58 extends outwardly from the lateral edges of the doorplate to be received in guiding relation within corresponding groovesformed by elements fixed to the forward edges of the housing adjacentthe door opening for guiding the door plate in movement between open andclosed positions. The guide flanges 58 are provided in the form of anelongate angle iron having one face 60 fixed, as by welding, to theouter edge portion of the door plate while the flange 58 extendsperpendicularly from the edge thereof.

The recess 62 in which the flange 58 is received is provided by anangular plate 64 in the form of an angle iron secured at one edge 66 tothe outer edge of the side plate 68 of the housing which defines thedoor opening, while the adjacent arm portion 70 of the angle ironextends inwardly with the flanged portion 72 extending rearwardly toprovide the recess 62 in which the guide flange 58 is received. Alsosecured to the inner wall of the side plate 68 but spaced rearwardly ofthe angle iron 64 is another member having a flanged portion 56extending inwardly from the side edge for a distance beyond the end ofthe recess 62 to define a slot between the flange 56 and the edge of theflange 72 through which the end structure of the door extends to beconfined within and between the elements with the wear plates 52 restingon the inner surface of the flange 56 for sliding support during openingand closing movements of the door.

It will be apparent from the structure described that the interfittingrelationship between the parts provides for a seal in the end structureof the door assembly which militates against flow of abrasive particlestherebetween with such force as to cause wear on the machine or elementsthereof since the particles lose their force when required to changedirections at least three times for passage through the space, as mightbe available between the flange 56 and the wear plate 52, between theedge of the door and the side wall of the machine and between the guideflange 58 and the elements 70 and 72 defining the recess in which theflange is received. Thus a sealing relationship is provided while alsomaking available an interconnected and guided relation which permits thedoor plate to be actuated by automatic means to between open and closedpositions.

Various means may be provided for actuating the door plate assembly tobetween raised or open and closed or lowered positions. One suchsuitable means, illustrated in Fig. l of the drawings, comprises aplurality of cables 74 secured at their free ends to an upper portion ofthe door plate while the other portions of the cables are wound aboutpulleys 76 fixed for rotational movement on a shaft 78 extendingcrosswise at the front of the housing between trunion members 80 mountedon the top wall of the housing. Means, such as a reversible electricmotor 82, is operatively connected to the shaft 78 for rotation thereofin one direction or the other to wind up the cable 74 for raising thedoor plate and for unwinding the cable to lower the door plate.

The bottom door section comprises a panel 84 formed of rubber or otherresilient, Wear-resistant material, having guide members 86 on the edgesthereof adapted to be received in sliding relation within guide channelsextending continuously downwardly from the lower edge of a similar guidesection, as described in the upper door plate assembly.

The lower edge of the flexible panel 84 is fixed, as by bolts 88, onto aclosing plate 90 of metal extending across the door opening and which isalso received in guidingrelation at its edges in the curvilinear grooveguide. Secured to the plate is a retainer rod 92 which extends crosswiseadjacent the inner wall of the flexible panel. Link members in the formof rigid metal bars 94 are pivoted at one end on the retainer 92 whilethe other end 96 is pivoted between yo-kes 98 on the end of actuatingarms 100 mounted for free rotational movement about pivot pins 102 fixedby closing plates 104 to a lower rearward portion of the frame of themachine. The actuating arms 100 are caused to rock about their pivots byan air cylinder 106 or other displacement means pivoted at its base end,at 108, upon a support 110, while the piston rod 112 is pivoted at itsouter end on a pin 114 on an arm rigid with the actuating arm 100 andoffset from its pivot 102.

Thus, displacement of the piston outwardly in the fluid cylinder willcause the actuating arm 100 to be rocked upwardly in a counter-clockwisedirection in Fig. 8 about its pivot 102 to cause its outer end to swingupwardly over a stillv greater distance to displace the link 94 and theattached resilient door panel 8-4 upwardly into contacting relation withthey lower edge of the door plate, or until otherwise stopped to closethe lower door opening. Displacement of the piston inwardly in thecylinder by flow of pressure fluid into the head end of the cylinderwill cause the actuating arm 100 to rock downwardly about its pivot tocause the door panel to be lowered within its guide to open position. Toassist in the guiding relation and to provide greater rigidity to theassembly, a guide plate 116 is fixed to extend downwardly from theclosing plate for travel in an extension of the guide slide formed inthe side wall of the housing, said guide plate 116 and slide preferablybeing in the form of a straight section for avoiding binding inoperation.

It will be understood that other equivalent means for actuating theupper and lower door panel sections may be employed without departingfrom the spirit of the invention. In the event that suflicient leveragecan be made available, as in units of smaller dimension or capacity,manual means may be employed for effecting displacement ,of thedescribed door elements between open and closed positions. Usually it isdesirable in closing the unit after loading to lower the top door plateprior to actuation of the bottom door section to raise the door sectionto closed position. Sequence of operation may be employed in actuatingthe sections to open position by raising the top and lowering thebottom.

It will be apparent that the widening of the door opening in the mannerdescribed will provide a number of material improvements over thestructures heretofore employed. Before the doors were widened the sealswere exposed to the erosion and wear caused by the abrasive material. Ifparticles entered the frame structure, the frame would become deformedwith resultant loss in sealing. An important concept of this inventionresides in the ability now to locate the seals outside of the dangerzone of the particles being thrown. Thus particles will find it morediflicult to enter the frame and the seals will not be exposed to Wear.

Where, in the past, entrance of abrasive particles or work into theframe or seals would cause distortions so that a sealing relation couldno longer be effected, now the conveyor seals are out of danger and theyare further made independent of the door seals so that one would nolonger have any effect upon the other. Thus it might become possible forthe seals to become deformed without affecting the ability of openingand closing the door, and vice versa.

It will be apparent that changes may be made in the details ofconstruction, arrangement and elements em ployed for operation withoutdeparting from the spirit of the invention, especially as defined in thefollowing claims.

1. In a cleaning machine of the type described having a housing, aconveyor in the housing upon which the work is supported, guide rollersat the front and back ends of the conveyor for guiding the conveyor inmovement, laterally spaced apart drum members which rotate with theconveyor between the front and back rollers to deflect the conveyor inits path of travel about the lower periphery thereof during travelbetween the front and back rollers and defining with the conveyor andhousing a confined space having an access opening extending from belowthe roller assembly at the front to the opening at the top, means forextending the access opening beyond the spaced drums comprising a shieldmember formed of rigid, wear resistant material having convergingcurvilinear portions one of which extends upwardly for a distanceconcentrically with the drum and outwardly to the adjacent side wall ofthe housing and the other of which extends forwardly to the accessopening concentrically with the front roller from the edge of theconveyor to the side wall of the housing, and means for securing theshield member rigidly to the housing in position of use.

2. A machine as claimed in claim 1 in which the shield member includesan apron downturned from the inner edge of the curvilinear portionconcentric with the roller and dimensioned to have a length to extendbelow the edge of the conveyor elements turning about said roller.

3. A machine as claimed in claim 1 in which the shield member includes aportion at the point of convergence which continues to extend rearwardlyinto the area between the drum and front roller to effect a clear lineof separation therebetween.

4. A machine as claimed in claim 1 in which the shield member includes aside plate integrally joining the outer edges of the convergingcurvilinear sections.

5. In a cleaning machine of the type described having a housing, aconveyor in the housing upon which the work is supported, guide rollersat the front and back ends of the conveyor for guiding the conveyor inmovement, laterally spaced apart drum members which rotate with theconveyor between the front and back rollers to deflect the conveyor inits path of travel about the lower periphery thereof during travelbetween the front and back rollers and defining with the conveyor andhousing a confined space having an access opening extending from belowthe roller assembly at the front to the opening at the top, a door framedefining the lateral edges of the access opening between the roller andthe top of the access opening in the housing comprising a rigid metalmember fixed to the outer edge of the housing and having a portionextending substantially perpendicularly inwardly from the side wall ofthe housing and a flange extending rearwardly substantiallyperpendicularly from the free edge of the inwardly extending portion todefine a groove therebetween and a slide plate fixed to the side wall ofthe housing and spaced inwardly from the metal member by an amountgreater than the length of the flange and dimensioned to be greater thanthe distance between the flange and the side wall of the housing toextend beyond the flange and provide a slotted portion therebetween, anda door panel in the form of a metal plate dimensioned to have a lengthcorresponding to the access opening between the roller and the top ofthe access opening in the housing and a width less than the distancebetween the side walls of the housing but greater than the distancebetween the flanged members defining the recess in the edges thereof anda guide flange fixed to the lateral edge portions of the door plate inposition to extend beyond the flange into the formed recesses forguiding the door in sliding movement between open and closed positionsand for sealing the space within the housing from the outside atmospherewhen the door is in closed position.

6. A machine as claimed in claim 5 which includes power operated meansand means interconnecting the power operated means with the door panelto effect vertical displacement of the door panel between open andclosed positions.

7. A machine as claimed in claim 5 which includes a lining on the innersurface of the door panel formed of a replaceable, resilient, wearresistant material.

8. A machine as claimed in claim 7 which includes hold-down straps onthe side of the lining opposite the door panel and which are connectedto the door panel to secure the lining in position of use therebetween.

9. A machine as claimed in claim 7 in which the lining terminates shortof the lateral edges of the door panel and which includes wear platesfixed to the inner surfaces of the door panel adjacent the lateral edgesthereof in position to engage the slide plates fixed to the side wallsof the housing.

10. in a cleaning machine of the type described having a housing, aconveyor in the housing upon which the work is supported, guide rollersat the front and back ends of the conveyor for guiding the conveyor inmovement, laterally spaced apart drum members which rotate with theconveyor between the front and back rollers to deflect the conveyor inits path of travel about the lower periphery thereof during travelbetween the front and back rollers and defining with the conveyor andhousing a confined space having an access opening extending from belowthe roller assembly at the front to the opening at the top, a lower doorframe defining the lateral edges of the access opening between theroller and the bottom edge of the access opening in the housing, a lowerdoor panel formed of a flexible wear resistant material dimensioned toextend crosswise between the lower door frame members and to have alength corresponding to the length of the access opening bounded by thelower door frame, a guide plate fixed to the lower edge of the flexibledoor panel, a linking means pivotally connecting the end of the linkwith the guide plate, an actuating arm pivoted at its rearward end uponthe housing, means pivotally interconnecting the free forward end of theactuator with the free end of the link, and means operatively engagingthe actuator arm intermediate its pivot for displacement of the arm forrocking movement about its pivot to effect opening and closing movementsof the door panel between lowered and raised positions respectively.

ll. A cleaning machine as claimed in claim 6 which includes a lower doorframe defining the lateral edges of the access opening between theroller and the bottom edge of the access opening in the housing, a lowerdoor panel formed of a flexible wear resistant material dimensioned toextend crosswise between the lower door frame members and to have alength corresponding to the length of the access opening bounded by thelower door frame, a guide plate fixed to the lower edge of the flexibledoor panel, a linking means pivotally connecting the end of the linkwith the guide plate. an actuating arm pivoted at its rearward end uponthe housing, means pivotally interconnecting the free forward end of theactuator with the free end of the link, and means o-peratively engagingthe actuator arm intermediate its pivot for displacement of the arm forrocking movement about its pivot to effect opening and closing movementsof the door panel between lowered and raised positions respectively inwhich, when the lower door panel is in raised position, the upper endthereof is in end to end relation with the lower edge of the door panel.

References Cited in the file of this patent UNITED STATES PATENTS2,533,265 Keeper Dec. 12, 1950

